This must be based off the same algorithm that chooses who appears in your Newsfeed, though this algorithm is more about social mapping and less about a person’s complete engagement.

The Newsfeed algorithm places people there based on your interactions with them and their level of overall engagement. The more engaged a person is, the higher the likelihood that they will get placement on your Newsfeed.

The social inbox will be based solely on your interactions and people you have linked in your profile, like parents, siblings and relationships.

So what is the social inbox? It is a more sophisticated form of mail filtering. Facebook will choose who it thinks are the people you most want to hear from and put those in your primary message box. Everyone else will get put into “other”.

This is not the same as spam. This is essentially Facebook prioritizing who you want to hear from the most. So in theory, bills, newsletters and that friend you don’t really like to talk to (but don’t have the heart to ask to stop sending you pictures of cat posters) will all get put into the “other” folder.

If Facebook incorrectly maps your friends, you can easily drag emails into or out of your preferred box.

The social mailbox will also let you easily control who is allowed to send you messages. You will be able to set controls in your privacy settings that establish who is and who isn’t.

This could be a great system for personal emails but maybe not great for business. Since most business emails are probably not in your “preferred users” delegation, you increase the likelihood of missing an email. However, if you have specific emails you need to be made aware of, moving a client into the preferred email box could help ensure that you keep track of all communications with that person and get alerted every time they email you.

So, I am still out on deciding if this will be a good application for business. But for personal communications I think it has the potential to dominate.